1. Field of the Invention
The present invention relates to a biometrics authentication system performing authentication of a living organism through the use of three-dimensional information.
2. Description of the Related Art
In recent years, the introduction of personal identification techniques (biometrics) using biometrics authentication into access control in a specific area or bank ATMs has begun. Therefore, an increase in crimes by fake ID cards or identity thefts has become a social issue, so the establishment of a method of personal identification capable of preventing forgery is desired.
As such a method of identifying a living organism, methods using faces, fingerprints, voiceprints, irises, veins and the like as authentication data have been proposed. For example, in a system using faces as authentication data, it is difficult to precisely capture characteristics of individuals due to physical conditions or makeup, and the characteristics of faces are easily changed due to growth or the like, so it is difficult to use the same data throughout a lifetime. Therefore, in authentication using faces, it is considered difficult to achieve high precision in general. Moreover, fingerprints, voiceprints, irises and the like are personal information which is relatively less changed; however, forgery such as duplication of a fingerprint through the use of a resin, recording and reproducing of a voiceprint through the use of a recorder, duplication of an iris pattern through the use of a high-definition printer has been perceived as an issue.
On the other hand, the shape pattern of veins under the skin of a finger or a palm hardly changes from approximately two or three years of age, so the shape pattern of the veins can be used as stable authentication data throughout a lifetime. Moreover, it is difficult to visually check veins directly from the skin surface, so various proposals have been made (for example, refer to Japanese Unexamined Patent Application Publication No. 2006-68328).
Now, in FIG. 11A, an example of a biometrics authentication system in a related art using the above-described vein authentication system is shown. In a technique in the related art, when a living organism 2 as an object subjected to authentication is held over a specified position, the vein pattern authentication can be performed. More specifically, when the living organism 2 is irradiated with near-infrared light by a light source 100 such as an LED (Light Emitting Diode) arranged on the lateral side (or the longitudinal side) of the living organism 2, optical absorption of blood hemoglobin flowing through veins can be observed. One refractive converging lens 101 forms an image of veins by such optical absorption on an image pickup device 102 such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor), and authentication data including a vein shape shown in FIG. 11B can be obtained.
Information used for authentication of a living organism is desired to have high reproducibility. Therefore, a technique of arranging a guide fixing a living organism (a finger) during authentication has been disclosed (for example, Japanese Patent No. 3630675). An authentication system according to Japanese Patent No. 3630675 has a configuration that when a finger is placed along a guide, a switch is pressed by an end of the finger, and when the switch is pressed, authentication starts. In such a configuration, the degree of freedom of a fingertip is limited in a lateral direction (referred to as an x direction), a longitudinal direction (referred to as a y direction) of the finger, and a direction orthogonal to these directions (referred to as a z direction), and the reproducibility can be improved.